it's part of a package put together by vice president joe biden and his white house task force. senior administration officials tell nbc news the biggest proposals will include universal background checks and a ban on high-capacity magazines. that's anything that carries more than ten rounds of ammunition. the president's also expected to ask congress to reinstate the assault weapons ban. as for possible executive orders, the president is expected to seek aggressive prosecution for those who break existing laws. for example, people who lie during background checks. the white house says the president will be joined by children from around the country who wrote letters to him following the newtown shootings. we're about to show, joe, because i still can't believe it, the ad that the nra has put out in the middle of this national conversation. but first, what do you think the president's chances are of being successful at getting this sled legislation through? >> well, it depends. we're on ever-shifting ground. things changed an awful lot after newtown. even the polls over the past